Bone Problems Flashcards
How does bacteria actually get into the bone?
Haematogenous spread
In osteomyelitis where exactly does the infection occur?
Bone + marrow
In children how does osteomyelitis occur?
Transient bacteraemia – >
seeding of metaphysis - usually at tibia/fibula
In adults how does osteomyelitis occur?
Open wound – >bacteraemia – > seed epiphysis
What is the most common site of infection in the bone? And why?
Metaphysis
Vascular supply is the best at metaphysis
therefore favours haematogenous spread
What is the most common bacteria cause of osteomyelitis?
Staph aureus
Are sexually active adults presents with osteomyelitis. What bacterial infection does he have?
Neisseria gonorrhoea
A patient with sickle-cell disease presents with osteomyelitis. What bacterial infection does he have?
Salmonella
Diabetic + IV drug user
who happens to wear rubber footwear and has a puncture in his foot
presents with osteomyelitis. What a bacterial infection does he have?
Pseudomonas
Patient presents with a cat/dog bite.
What bacterial infection does he have?
Apart from the obvious what else does he have?
Osteomyelitis
Cellulitis septic arthritis endocarditis meningitis
COSEM..
A patient with TB presents with osteomyelitis. It has affected his lumbar vertebrae. What does he have? And where does the spread come from?
Pots disease
Haematogenous spread from primary lung focus
What are the clinical features of osteomyelitis?
Bone pain, fever, leucocytosis,
Warmth, erythema, swelling
On x-ray what do is see for osteomyelitic infection?
Lytic focus
(Liquefactive necrosis -Sequestrum Brodies abscess)
surrounded by sclerosis – Involucrum
Treatment for osteomyelitis?
How do you diagnose it?
Surgery + antibiotics
Blood culture
Explain how we form that reactive bone that causes sclerosis?
Bacteria – > inflammatory exudate @marrow ->
increased intermedullary pressure
+
exudate into bone cortex – >
neutrophils enzymatically destroyed by bone – >
Rupture through periosteum->interrupt periosteal BF
sequestral/Devitalisation of bone - leave pieces – >
Chronic disease = reactive bone formation @periosteoma = involucrum
+
Brody’s abscess
– >From draining sinus tract formation @skin =
high risk of squamous CC + Sinus tract orifice
Where does avascular necrosis usually occur?
Scaphoid
Humeral
Femoral (Most common)
Talus
Explain how an old woman develops avascular necrosis in the femoral head?
Insufficiency of Retinacular arteries of the medial circumflex femoral artery
In avascular necrosis what is the necrosis due to?
Decreased blood flow – >ischaemic necrosis @bone
What are the causes of avascular necrosis?
ASEPTIC
Alcoholism
Sickle-cell disease – dactylitis =
vasoocclusive crisis @both hands and feet
Exo/endogenous corticosteroids – >fat embolus – >occlude microcirculation
Pancreatitis
Trauma – >decreased blood flow
Idiopathic = Legg Calvé Perthe disease
Caisson disease
Explain Legg Calvé perthes disease.
AAN of ossification centres – epiphysis
@ kids 3–10 years
of femoral head – knee pain/limp
Explain Caisson disease.
Gas embolus – nitrogen – >
precipitate out of blood – > lodge in bone – > AAN
What is the complication of avascular aseptic necrosis
AAN under joint – >increased risk of joint damage – >osteoarthritis
AAN under joint – >fracture
Explain the difference between a peritrochanteric and subcapsular fracture.
PeriTrochanteric fracture = extracapsular = no blood supply to femoral head – > no AAN
Sub capsular fracture = disrupts blood supply –> retinacular art. of medial circumflex fem. artery – > AAN
Treatment for avascular aseptic necrosis
Joint replacement
Core decompression
Bone graft/BISPHOSPHONATES
That’s vertebral osteomyelitis where on the vertebrae are the most common places? What can you form in these places?
Lumbar >thoracic >cervical
Abscess
Explain how osteomyelitis leads to septic arthritis
Osteomyelitis – >infection breaks through cortex – > post discharge into joint = septic arthritis
What is a fracture?
Breach in structural continuity of bone
What are the two main classifications according to its relation to the surrounding tissue
Simple + compound
What is a simple/closed fracture?
The skin/mucous membrane overlying the bone is intact
I.e. does not have contact with the external environment
Explain what a compound/open fracture is
A fracture that is in contact with the external environment
More likely to be infected
What does comminuted mean?
> 2 fragments
What does complicated fracture mean?
Involve viscus/Artery/nerve
What is a pathological fracture?
Fracture @ abnormal bone i.e. osteoporosis/tumour
What is a stress fracture?
Repeated application of mind of force – >slowly developing fracture
What is a greenstick fracture?
Usually at children
One side of bone = fractured – >bent but intact
What are the four processes in the bone healing
Haematoma
Inflammation
Repair
Remodelling
Explain haematoma formation
Tear medullary blood vessels – endosteal + periosteal – >
Haemorrhage into marrow space
Haematoma into soft tissue
Periosteal stripping
Explain inflammation in bone healing
Fibrin clot form = Rich in chemoattractants ->
Neutrophils/macrophages migrate = Clear debris ->
Neovascularisation + fibroblast proliferation = Fibrovascular granulation – >
Mesenchymal precursor cells mature into osteoblasts -> migrate in to granulation tissue
Osteoblast deposit osteoid collagen in haphazard fashion = woven bone
Explain repair
Outside part of fracture = covered by callus = fibro-cartilage
Inside part of fracture = covered by internal callus = no cartilage
Highly vascular
Explain remodelling
Osteoclast result she can osteoblast synthesis ->
Remove XS callous +
replace woven with the lamella (compact + organised)
Increased bone strength + vascularity normal
What are the principles of fracture management
Reduce fracture
Immobilise
Rehabilitate
Types of fracture fixation
Slings
Cost
Intra/extra medullary devices
External fixation
Factors influencing fracture healing?
Patient: smoking age nutrition drugs
Tissue: bone type/site/pathology
Treatment: opposition/stability/micromotion
What are the early local complications of fractures
Vessel damaged nerve damage infection
What are the early general complications of fractures
Hypovolaemic shock
A RDS
Venus Trumbull embolism
embolism Fat
What are the late local complications of fractures
Malunion
Delayed union/Non-union
What are the late general complications of fractures
Poor mobility/income
